Accession Number : ADA305069

Title :   Flight Service Evaluation of Kevlar-49 Epoxy Composite Panels in Wide-Bodied Commercial Transport Aircraft - Fourth Annual Flight Service Report.

Descriptive Note : Contractor rept.,

Corporate Author : LOCKHEED-CALIFORNIA CO BURBANK

Personal Author(s) : Stone, R. H.

PDF Url : ADA305069

Report Date : APR 1978

Pagination or Media Count : 66

Abstract : Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after four years' service, and found to be performing satisfactorily. There are six Kevlar-49 panels on each aircraft, including sandwich and solid laminate wing-body panels, and 150 deg C (300 deg F) service aft engine fairings. The three L-1011s are one each of Eastern, Air Canada, and TWA aircraft. The fairings have accumulated a total of 32,472 hours, with one ship set having 13,347 hours service as of January 31, 1978. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were all found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. A concurrent investigation has been conducted by NASA-Langley on Kevlar-49/epoxy coupons exposed to outdoor environment over a three year period at various locations providing a variety of climatic conditions. Weight changes and retention of mechanical properties were determined after one and three years exposure. A net weight loss has occurred due to ultraviolet effects on the unpainted specimens. Mechanical property retentions have been satisfactory with most specimens retaining well over 80% of their original value. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

Descriptors :   *EPOXY COMPOSITES, *TRANSPORT AIRCRAFT, FLIGHT TESTING, FIBERGLASS, ULTRAVIOLET RADIATION, COMMERCIAL AIRCRAFT, STRESS ANALYSIS, AIRCRAFT MAINTENANCE, EXPOSURE(GENERAL), STRUCTURAL ANALYSIS, CRACKS, DAMAGE ASSESSMENT, IMPACT STRENGTH, DEFECTS(MATERIALS), HOLES(OPENINGS), FLEXURAL STRENGTH, EPOXY LAMINATES, MOISTURE, FAILURE(MECHANICS), COMPRESSIVE STRENGTH, SKIN(STRUCTURAL), WEIGHT REDUCTION, WING BODY CONFIGURATIONS, ELONGATION, DELAMINATION, AIRCRAFT PANELS, SANDWICH PANELS, HONEYCOMB CORES, SHEAR STRENGTH, FAIRINGS.

Subject Categories : Transport Aircraft
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE